Method for manufacturing color cathode ray tube and manufacturing apparatus therefor

Abstract

A method for manufacturing a color cathode ray tube capable of surely applying a predetermined tension force to a shadow mask and preventing the generation of wrinkles and a manufacturing apparatus of the color cathode ray tube. The method includes applying a compression force to a mask frame formed in a frame shape in the direction in which a gap between at least a pair of facing sides is reduced; and welding and fixing a shadow mask to the upper surface of the mask frame with a tension force applied in the direction opposite to the compression force. In this method, a place to which the compression force is applied is the upper end of the external surface of the mask frame. Thus, a repulsion force in the direction in which a shadow mask is stretched can surely be obtained after the compression force is released, as compared with the case where the same level of compression force is applied to the lower end. Consequently, it is possible to prevent the deterioration of the tension force of the shadow mask.

What is claimed is: 
     
       1. A method for manufacturing a color cathode ray tube comprising: applying a compression force to a mask frame that is formed in a frame shape in the direction in which a gap between at least a pair of facing sides is reduced; and   fixing a shadow mask to an upper surface of said mask frame by welding while a tension force is applied in a direction opposite to said compression force, wherein a place to which said compression force is applied is an upper end of an external surface of said mask frame, and wherein said compression force is applied by bringing a flexible plate member into a direct contact with an entire length of one side of said mask frame.       
     
     
       2. A method for manufacturing a color cathode ray tube comprising: applying a compression force to a mask frame that is formed in a frame shape in the direction in which a gap between at least a pair of facing sides is reduced; and   fixing a shadow mask to an upper surface of said mask frame by welding while a tension force is applied in a direction opposite to said compression force, wherein a place to which said compression force is applied is an upper end of an external surface of said mask frame, and wherein said shadow mask is held at a predetermined position by a holding means before a tension force is applied to said shadow mask, thereby positioning said shadow mask.       
     
     
       3. The method for manufacturing a color cathode ray tube according to claim 2, wherein said holding means uses a magnet adhering to said shadow mask. 
     
     
       4. The method for manufacturing a color cathode ray tube according to claim 2, wherein said holding means adheres to said shadow mask by a suction force by vacuum pulling. 
     
     
       5. The method for manufacturing a color cathode ray tube according to claim 2, wherein said shadow mask is held in a curved shape by said holding means. 
     
     
       6. The method for manufacturing a color cathode ray tube according to claim 5, wherein said curved shape is held by adhering to said shadow mask to a curved portion formed on said holding means. 
     
     
       7. The method for manufacturing a color cathode ray tube according to claim 2, wherein said shadow mask is stretched outward with respect to its center by using said holding means in a state in which it is fixed to said holding means, thereby fixing said shadow mask to said holding means while being stretched. 
     
     
       8. A manufacturing apparatus, comprising: means for applying a compression force to a mask frame that is formed in a frame shape in the direction in which a gap between at least a pair of facing sides is reduced, and   means for fixing a shadow mask to an upper surface of said mask frame by welding with a tension force applied in a direction opposite to said compression force;   said apparatus comprising a pressure device for applying said compression force, wherein a place to which said compression force is applied is an upper end of an external surface of said mask frame, and wherein said pressure device has a flexible plate member having a length ranging a full length of one side of said mask frame, and application of said compression by said pressure device is carried out by bringing a flexible plate member into a direct contact with an entire length of one side of said mask frame.     
     
     
       9. A manufacturing apparatus, comprising: means for applying a compression force to a mask frame that is formed in a frame shape in the direction in which a gap between at least a pair of facing sides is reduced, and   means for fixing a shadow mask to an upper surface of said mask frame by welding with a tension force applied in a direction opposite to said compression force;   said apparatus comprising a pressure device for applying said compression force, wherein a place to which said compression force is applied is an upper end of an external surface of said mask frame, and wherein said apparatus has a holding means for holding said shadow mask at a predetermined position, and said shadow mask is held at a predetermined position by said holding means before a tension force is applied, thereby positioning said shadow mask.     
     
     
       10. The manufacturing apparatus according to claim 9, wherein said holding means uses a magnet adhering to said shadow mask. 
     
     
       11. The manufacturing apparatus according to claim 9, wherein said holding means adheres to said shadow mask by using a suction force by vacuum pulling. 
     
     
       12. The manufacturing apparatus according to claim 9, wherein said shadow mask is held in a curved shape by said holding means. 
     
     
       13. The manufacturing apparatus according to claim 12, wherein said curved shape is held by adhering said shadow mask to a curved portion formed on said holding means. 
     
     
       14. The manufacturing apparatus according to claim 9, wherein said shadow mask is stretched outward with respect to its center by said holding means in a state in which it is fixed to said holding means, thereby fixing said shadow mask to said holding means while being stretched.